Assessment of hydrogen storage in activated carbons produced from hydrothermally treated organic materials

Abstract

Available online xxx Keywords:Hydrogen storage Adsorption Hydrothermal carbonisation KOH activation Microporous activated carbons a b s t r a c t 12 activated carbons (ACs) were prepared by KOH activation using hydrochars as precursors. These hydrochars were prepared by hydrothermal carbonisation (HTC) of sucrose solutions at concentrations ranging from 0.2 to 1.6 mol L À1 . The KOH to hydrochar weight ratio (W) was varied from 1 to 5, and the activation temperature was set to 1023 K. ACs texture was assessed by nitrogen and carbon dioxide adsorption at 77 and 273 K, respectively; pore size distribution was calculated by using both isotherms and the SAIEUS© software. ACs with surface areas between 790 and 2240 m 2 g À1 were obtained. Hydrogen excess adsorption was determined at 298 K and pressures up to 10 MPa in a volumetric device, and the isosteric heat of adsorption (Q st ) was calculated for four ACs, using hydrogen isotherms obtained at 278, 298 and 308 K. Potassium intercalation between graphitic planes was assumed to account for the high Q st values, 7e8 kJ mol À1 . Hydrogen uptake at 2 MPa was compared with hydrogen adsorption data of 38 other ACs reported in the open literature. Hydrogen adsorption fundamentally depends on micropore volume and preliminary HTC did not enhance hydrogen storage although it could be a good strategy for doping carbon with heteroelements.

Hydrogen storage in carbon materials—A review

“…All the samples exhibit higher microporous volumes than that of mesoporous volumes, and the total surface area was observed in the range of 305 to 687 m 2 g −1 . As the surface area get enhanced by KOH activation, the maximum storage capacity of 2.14 wt% was observed at 19 bar and 77 K. Schaefer et al prepared 12 different samples of AC using hydrochars. Heteroelements can be mixed nicely with carbon by hydrothermal carbonization method but unfortunately, it is does not improve the hydrogen adsorption because fundamentally the hydrogen adsorption linearly depends on micropore volume as well as surface area.…”

“…As the surface area get enhanced by KOH activation, the maximum storage capacity of 2.14 wt% was observed at 19 bar and 77 K. Schaefer et al 61 nicely with carbon by hydrothermal carbonization method but unfortunately, it is does not improve the hydrogen adsorption because fundamentally the hydrogen adsorption linearly depends on micropore volume as well as surface area. The experimentally measured maximum hydrogen adsorption reported was 0.59 wt% at 10 bar.…”

Scope of doped mesoporous (<10 nm) surfactant‐modified alumina templated carbons for hydrogen storage applications

“…Comparatively low cost, easy availability, and good chemical stability are added advantages . Researchers have reported various porous carbon materials for hydrogen storage application, such as carbon nanotube, activated carbon, metal organic framework, and templated carbons . Majority of the reported hydrogen storage materials are microporous having high surface area.…”

“…6,7 Researchers have reported various porous carbon materials for hydrogen storage application, such as carbon nanotube, activated carbon, metal organic framework, and templated carbons. [8][9][10][11][12] Majority of the reported hydrogen storage materials are microporous having high surface area. However, the high surface area mesoporous carbons (2-20 nm) are also reported recently.…”

Preparation and evaluation of modified cyanobacteria-derived activated carbon for H2 adsorption

“…1,2 It is the molecule that delivers the largest amount of energy on combustion with oxygen, in which only water is generated. 1,2 It is the molecule that delivers the largest amount of energy on combustion with oxygen, in which only water is generated.…”